Pressing mechanism, composite current collector preparation apparatus and method, and battery production system

Abstract

The present application relates to a pressing mechanism, a composite current collector preparation apparatus and method, and a battery production system. Air suction holes are formed on a roller surface of a supporting roller and / or a pressing roller. When the pressing roller and the supporting roller cooperatively press a conductive layer and a substrate layer which are bonded to each other, air can be evacuated from the surface of the conductive layer and / or the substrate layer by means of the air suction holes, causing the conductive layer and the substrate layer to be pressed and suctioned simultaneously, thereby accelerating the removal of gas from between the conductive layer and the substrate layer, reducing bubbles between the conductive layer and the substrate layer, improving a binding force between the conductive layer and the substrate layer, reducing a risk of stripping of the conductive layer, and improving battery performance.

Description

Extrusion mechanism, composite current collector preparation device, method and battery production system

[0001] Related applications

[0002] This application claims priority to Chinese patent application No. 2024100259787, filed on January 8, 2024, entitled “Extrusion mechanism, composite current collector preparation device, method and battery production system,” the entire text of which is hereby incorporated by reference. Technical Field

[0003] The present application relates to the field of battery production technology, and in particular to an extrusion mechanism, a composite current collector preparation device and method, and a battery production system. Background Art

[0004] The current collector is an important component of the battery. It not only provides support for the active material layer, but also collects the current generated by the active material layer for external output. With the improvement of battery reliability requirements, composite current collectors have also been proposed. Composite current collectors refer to the structure obtained by combining the conductive layer and the polymer substrate layer. If the conductive layer and the polymer substrate layer are bonded by glue, due to the limitations of the structural design of traditional equipment, the conductive layer is easy to peel off and the bonding force is reduced, which leads to the problem of reduced battery performance.

[0005] The above statements are only used to provide background information related to the present application and do not necessarily constitute prior art.

[0006] Summary of the Invention

[0007] Based on this, it is necessary to provide an extrusion mechanism, a composite current collector preparation device, a method and a battery production system to improve the bonding between the conductive layer and the substrate layer, reduce the risk of peeling, and improve battery performance.

[0008] In the first aspect, the present application provides an extrusion mechanism, which includes: a support roller; an extrusion roller, which is used to extrude the conductive layer and the substrate layer that are bonded to each other between the support roller and the extrusion roller; wherein, at least one of the support roller and the extrusion roller is provided with an exhaust hole for connecting to a suction device on the roller surface arranged circumferentially around its own axis.

[0009] The above-mentioned extrusion mechanism is provided with exhaust holes on the roller surface of the support roller and / or the extrusion roller. When the extrusion roller and the support roller cooperate to extrude the conductive layer and the substrate layer that are bonded to each other, the surface of the conductive layer and / or the substrate layer can be exhausted through the exhaust holes, so that the conductive layer and the substrate layer are squeezed and sucked at the same time, thereby accelerating the escape of gas between the conductive layer and the substrate layer, reducing bubbles between the conductive layer and the substrate layer, improving the bonding force between the conductive layer and the substrate layer, reducing the risk of peeling of the conductive layer, and helping to improve battery performance.

[0010] In some embodiments, the support rollers and / or squeeze rollers with suction holes are provided with ventilation channels extending along their respective axes, the ventilation channels communicating with the corresponding suction holes. This design, with the introduction of ventilation channels, facilitates connection of the suction holes to external suction equipment, enabling stable suction of the conductive layer and / or substrate layer.

[0011] In some embodiments, the support roller or squeeze roller includes two or more extraction holes, with at least some of the extraction holes spaced apart. This design, in which at least some of the extraction holes are spaced apart, can expand the extraction range, resulting in more uniform degassing between the conductive layer and the substrate layer, thereby improving the lamination quality of the composite current collector.

[0012] In some embodiments, among the spaced apart exhaust holes, the distance between two adjacent exhaust holes is denoted as L, where 5 mm ≤ L ≤ 50 mm.

[0013] In some embodiments, the spacing L further satisfies the condition: 10 mm ≤ L ≤ 30 mm.

[0014] With this design, the spacing L is controlled between 5 mm and 50 mm, so that the design of the exhaust holes can effectively take into account both the exhaust effect and the lamination quality between the conductive layer and the substrate layer.

[0015] In some embodiments, the support roller or squeeze roller includes two or more exhaust holes, with at least some of the exhaust holes being spaced apart around the circumference of the corresponding axis. This design, in which at least some of the exhaust holes are spaced apart around the circumference of the axis, allows the support roller or squeeze roller to have a suction function along its circumference. This allows the support roller or squeeze roller to draw suction from the conductive layer or substrate layer as it rotates, thereby improving exhaust efficiency.

[0016] In some embodiments, the area of ​​the exhaust holes on the roller surface of the support roller or the squeeze roller is recorded as S, where 0.00785 mm 2 ≤S≤0.785mm 2 .

[0017] In some embodiments, the hole area S also meets the following conditions: 0.1mm 2 ≤S≤0.5mm 2 .

[0018] In some embodiments, the air extraction hole is configured as a circular hole, and the diameter of the air extraction hole is 0.1 mm to 1 mm.

[0019] This design controls the area of ​​the exhaust hole to 0.00785mm 2 ~0.785mm 2 Effective exhaust can be achieved; at the same time, the probability of glue overflow or embossing during the pressing process can be reduced, thereby improving the pressing quality.

[0020] In some embodiments, there are two or more squeezing rollers, all of which are spaced apart around the axis of the support roller. This design, with the inclusion of two or more squeezing rollers, allows for multiple squeezing operations on the same portion of the conductive layer and substrate layer, enhancing the lamination effect and tightly bonding the conductive layer to the substrate layer. It also enhances degassing and reduces the likelihood of the conductive layer peeling off.

[0021] In some embodiments, a pressing path is formed between all the squeezing rollers and the supporting rollers for the laminated conductive layer and the substrate layer to pass through. The central angle of the pressing path on the supporting roller is denoted as θ, where 180°≤θ<360°.

[0022] In some embodiments, the central angle θ further satisfies the condition: 200°≤θ≤300°.

[0023] With this design, the central angle corresponding to the pressing path is controlled to be greater than or equal to 180°, which can increase the running angle of the conductive layer and the substrate layer on the support roller, which is beneficial to improving the pressing and exhaust effects of the composite current collector.

[0024] In some embodiments, the cross-sectional area of ​​at least one squeezing roller, perpendicular to its axis, gradually increases and then decreases from one end of the squeezing roller to the other. This design, where the at least one squeezing roller is larger in the middle and smaller at the ends, allows for a smoother lamination of the conductive layer and substrate layer during lamination. It also facilitates the transfer of bubbles in the glue toward the ends, improving degassing.

[0025] In some embodiments, in a plane passing through the axis of the squeezing roller, a projection of the roller surface of the squeezing roller includes at least one contour line, and an angle between the contour line and the axis of the squeezing roller is denoted as β, wherein 1°≤β≤5°.

[0026] In some embodiments, the angle β further satisfies the condition: 2°≤β≤4°.

[0027] With this design, the angle β is reasonably controlled between 1° and 5°, which improves the flattening effect of the conductive layer and the substrate layer and improves the lamination quality.

[0028] In some embodiments, the extrusion mechanism further includes a heating element for heating the surfaces of the support roller and / or the extrusion roller. This design, incorporating the heating element, increases the surface temperature of the conductive layer and / or the substrate layer, softening the glue and improving bonding performance. It also facilitates the escape of bubbles in the glue, enhancing degassing.

[0029] In some embodiments, there are at least two support rollers and squeeze rollers, all of which are arranged side by side and spaced apart, with each support roller working in conjunction with at least one squeeze roller. This design, with the inclusion of two or more support rollers, allows the conductive layer and substrate layer to be laminated sequentially on different support rollers, enhancing bonding strength and improving structural stability.

[0030] In a second aspect, the present application provides a composite current collector preparation device, comprising any one of the above extrusion mechanisms.

[0031] In some embodiments, the composite current collector preparation apparatus further includes a punching mechanism located upstream of the extrusion mechanism along the path of the substrate layer or the conductive layer, and configured to punch holes in the conductive layer and / or substrate layer. This design, through the punching mechanism, creates holes in the conductive layer and / or substrate layer, facilitating gas escape from the holes during lamination, further enhancing the gas venting effect and thereby making the bond between the conductive layer and the substrate layer more stable.

[0032] In some embodiments, the composite current collector preparation apparatus further includes a glue coating mechanism located upstream of the extrusion mechanism along the substrate layer or conductive layer path and configured to apply glue to the conductive layer and / or substrate layer. This design allows for a stable application of glue to the conductive layer and / or substrate layer, ensuring a stable bond between the conductive layer and the substrate layer.

[0033] In some embodiments, the composite current collector preparation apparatus further includes a surface treatment mechanism located upstream of the glue coating mechanism and configured to improve the surface energy of the conductive layer and / or substrate layer. This design improves the surface energy of the conductive layer and / or substrate layer through the surface treatment mechanism, enhancing adhesion to the glue, thereby ensuring a stable bond between the conductive layer and substrate layer and improving structural stability.

[0034] In some embodiments, the composite current collector preparation apparatus further includes a baking mechanism, located downstream of the glue coating mechanism, for drying the conductive layer and / or substrate layer after glue coating. This design, including the baking mechanism, accelerates the volatilization of the solvent in the glue, softens the glue, improves bonding properties, and thereby enhances the bonding strength between the conductive layer and the substrate layer.

[0035] In some embodiments, the composite current collector preparation apparatus further includes a passivation mechanism for passivating at least one surface of the conductive layer. This design and the introduction of the passivation layer improve the corrosion resistance of the conductive layer during long-term electrolyte circulation and storage, reducing the risk of delamination of the composite current collector during long-term electrolyte immersion. It also enhances the conductive layer's adhesion to the glue, further improving structural stability.

[0036] In some embodiments, the composite current collector preparation apparatus further includes a first unwinding mechanism and a second unwinding mechanism, the first unwinding mechanism and the second unwinding mechanism being used to release the conductive layer and the substrate layer, respectively. This design and the introduction of the first unwinding mechanism and the second unwinding mechanism allow for continuous and stable preparation of the composite current collector.

[0037] In some embodiments, the composite current collector preparation device further includes a winding mechanism for winding the laminated conductive layer and substrate layer output by the extrusion mechanism. This design facilitates storage of the composite current collector through the winding mechanism.

[0038] In a third aspect, the present application provides a method for preparing a composite current collector, which includes the following steps: drilling holes through the surface of the substrate layer and / or the conductive layer; applying glue to the surface of the substrate layer and / or the conductive layer; stacking and bonding the substrate layer and the conductive layer; and extruding and evacuating the stacked substrate layer and the conductive layer.

[0039] In some embodiments, the step of squeezing and evacuating the laminated substrate layer and conductive layer includes: passing the laminated substrate layer and conductive layer between a support roller and a squeeze roller; using the support roller and squeeze roller to squeeze and convey the substrate layer and conductive layer; and evacuating air from the evacuation holes on the roller surface of the support roller and / or squeeze roller. This design, with the support roller and squeeze roller, allows for simultaneous squeezing and evacuation during the lamination process, accelerating the discharge of gas from the holes in the conductive layer and / or substrate layer, improving the evacuation effect, and ensuring stable bonding between the conductive layer and substrate layer.

[0040] In some embodiments, during the step of extruding and conveying the substrate layer and the conductive layer via the support roller and the squeeze roller, at least two squeeze rollers are included. The substrate layer and the conductive layer sequentially pass between each squeeze roller and the support roller, and the pressure applied by each squeeze roller on the same support roller gradually increases along the direction of the substrate layer's travel. This design, with the inclusion of two or more squeeze rollers, allows for multiple squeezes on the same portion of the conductive layer and the substrate layer, enhancing the lamination effect and tightly bonding the conductive layer to the substrate layer. It also enhances degassing and reduces the likelihood of the conductive layer peeling off.

[0041] In some embodiments, after applying glue to the surface of the substrate layer and / or the conductive layer, the process further includes baking the glue-coated substrate layer and / or the conductive layer. This baking process can reduce the generation of bubbles and improve the adhesive properties of the glue, ensuring a tight connection between the conductive layer and the substrate layer.

[0042] In some embodiments, the baking parameters include at least one of the following: a blowing speed of 0.5 m / s to the surface of the substrate layer and / or the conductive layer; 3 / min~5m 3 / min; the blowing time on the surface of the substrate layer and / or the conductive layer is 2s to 10s; and the baking temperature is 80°C to 150°C. Thus, by properly controlling the baking temperature, blowing speed, and blowing time, the residual solvent in the glue is further reduced, the adhesive properties of the glue are improved, and the bonding strength between the conductive layer and the substrate layer is thereby enhanced.

[0043] In some embodiments, prior to applying glue to the surfaces of the substrate layer and / or the conductive layer, the substrate layer and / or the conductive layer are subjected to a corona treatment. This design and the introduction of the corona treatment improve the corrosion resistance of the conductive layer during long-term electrolyte circulation and storage, reducing the risk of delamination of the composite current collector during long-term electrolyte immersion. It also improves the adhesion of the conductive layer to the glue, further enhancing the stability of the structure.

[0044] In a second aspect, the present application provides a battery production system, which includes any one of the composite current collector preparation devices described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0046] FIG1 is a schematic structural diagram of an extrusion mechanism described in some embodiments of the present application.

[0047] FIG2 is a schematic structural diagram of the support roller described in some embodiments of the present application.

[0048] FIG3 is a schematic structural diagram of the squeezing roller described in some embodiments of the present application.

[0049] FIG4 is a first structural diagram of a composite current collector preparation device described in some embodiments of the present application.

[0050] FIG5 is a second structural schematic diagram of the composite current collector preparation device described in some embodiments of the present application.

[0051] FIG6 is a third structural diagram of the composite current collector preparation device described in some embodiments of the present application.

[0052] FIG7 is a flow chart 1 of the method for preparing a composite current collector described in some embodiments of the present application.

[0053] FIG8 is a second flow chart of the method for preparing a composite current collector described in some embodiments of the present application.

[0054] Figure 9 is a flow chart 3 of the composite current collector preparation method described in some embodiments of the present application. 100, extrusion mechanism; 10, support roller; 11, exhaust hole; 12, air vent; 13, lamination path; 20, extrusion roller; 21, contour line; 30, punching mechanism; 40, gluing mechanism; 50, baking mechanism; 60, surface treatment mechanism; 70, passivation mechanism; 80, first unwinding mechanism; 81, second unwinding mechanism; 90, rewinding mechanism; 200, substrate layer; 300, conductive layer. DETAILED DESCRIPTION

[0055] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0056] In the description of this application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0057] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0058] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0059] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0060] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.

[0061] Currently, market developments indicate that power batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As power battery applications continue to expand, market demand is also growing.

[0062] During battery production, active materials are typically coated onto current collectors to create the desired positive and negative electrodes. Current collectors can be conventional metal foils, such as aluminum or copper foil, or composite current collectors. Composite current collectors consist of a conductive layer attached to a substrate layer, for example, by adhesive bonding.

[0063] Since there will be more or less residual gas in the glue, when the conductive layer is bonded and pressed onto the base layer, it is difficult for the gas to escape from the glue, resulting in incomplete adhesion between the base layer and the conductive layer. The bonding force between the two is poor, resulting in the risk of sporadic peeling of the conductive layer.

[0064] Based on this, in order to effectively solve the problem that the conductive layer on the surface of the composite current collector is at risk of peeling due to glue bonding, the present application provides an extrusion mechanism, and an exhaust hole is set on the roller surface of the support roller and / or the extrusion roller. When the extrusion roller and the support roller cooperate to extrude the conductive layer and the substrate layer that are bonded to each other, the surface of the conductive layer and / or the substrate layer can be exhausted through the exhaust hole, so that the conductive layer and the substrate layer are squeezed and sucked at the same time, thereby accelerating the escape of gas between the conductive layer and the substrate layer, reducing bubbles between the conductive layer and the substrate layer, improving the bonding force between the conductive layer and the substrate layer, reducing the risk of peeling of the conductive layer, and helping to improve battery performance.

[0065] According to some embodiments of the present application, referring to FIG. 1 , a squeezing mechanism 100 is provided. The squeezing mechanism 100 includes a support roller 10 and a squeezing roller 20. The squeezing roller 20 and the support roller 10 are used to squeeze the conductive layer 300 and the substrate layer 200 that are bonded to each other. At least one of the support roller 10 and the squeezing roller 20 has an air extraction hole 11 disposed on its roller surface, which is arranged circumferentially around its axis, for communicating with a suction device.

[0066] The support roller 10 and the squeezing roller 20 refer to structures acting on opposite sides of the composite current collector, so that the composite current collector is subjected to pressure along its own thickness direction to achieve a stable combination of the conductive layer 300 and the substrate layer 200, wherein the support roller 10 and the squeezing roller 20 can both be cylindrical structures.

[0067] To ensure that the conductive layer 300 and substrate layer 200 are conveyed forward and continuously pressed together, the support roller 10 and squeeze roller 20 are capable of rotating about their respective axes, with the rotation directions being opposite. Furthermore, the linear speed of the support roller 10 and the linear speed of the squeeze roller 20 can be kept consistent. This prevents wrinkling or cracking of the composite current collector surface during pressing due to inconsistent roller linear speeds.

[0068] The suction device is a device that provides power for suctioning the surface of the conductive layer 300 and / or substrate layer 200, and can be, for example, but not limited to, a vacuum pump. The suction device and the suction holes 11 can be connected via a hose, or a flow channel can be provided on the support roller 10 or the squeeze roller 20 to connect the suction device and the suction holes 11.

[0069] During the lamination process, the suction holes 11 draw air from the surface of the conductive layer 300 and / or the substrate layer 200 under the action of a suction device, thereby accelerating the escape velocity of gas during the lamination process. To enhance the suction effect, the surface of the conductive layer 300 and / or the substrate layer 200 may be perforated after lamination. This allows the gas to easily escape through the holes in the conductive layer 300 or the substrate layer 200 under the action of suction, thereby enhancing the exhaust effect.

[0070] The holes punched in the conductive layer 300 and / or the substrate layer 200 can have various hole sizes and distributions. For example, the hole diameters in the conductive layer 300 and / or the substrate layer 200 can be between 50 μm and 500 μm. This allows for gas escape during the lamination process and reduces glue overflow from the holes, thereby enhancing the bonding strength between the conductive layer 300 or substrate layer 200 and the glue. The spacing between the holes in the conductive layer 300 and / or the substrate layer 200 can be controlled to be between 5 mm and 50 mm, for example.

[0071] In addition, the composite current collector can be laminated in either a one-step or two-step process. One-step lamination involves gluing two conductive layers 300 onto both surfaces of the substrate layer 200, and inserting the composite structure between the support roller 10 and the squeeze roller 20. Two-step lamination involves gluing a conductive layer 300 onto one surface of the substrate layer 200, inserting the conductive layer 300 into the space between the support roller 10 and the squeeze roller 20. After lamination, another conductive layer 300 is glued onto the other surface of the substrate layer 200, and then inserted into the space between the support roller 10 and the squeeze roller 20 again.

[0072] It should also be noted that substrate layer 200 refers to the structure that supports the composite current collector, and its material can be selected from at least one of an organic polymer insulating material, an inorganic insulating material, and a composite material. Among them, organic polymer insulating materials include at least one of polyamide, polyterephthalate, polyimide, polyethylene, polypropylene, polystyrene, polyvinyl chloride, acrylonitrile-butadiene-styrene copolymer, polybutylene terephthalate, poly(p-phenylene terephthalamide), polypropylene, polyoxymethylene, epoxy resin, phenolic resin, polytetrafluoroethylene, polyvinylidene fluoride, silicone rubber, and polycarbonate. Inorganic insulating materials include at least one of aluminum oxide, silicon carbide, and silicon dioxide. Composite materials include at least one of epoxy resin glass fiber reinforced composite materials and polyester resin glass fiber reinforced composite materials.

[0073] The conductive layer 300 is a conductive structure that collects the current generated by the active material layer for external output. In the electrode, the side of the conductive layer 300 facing away from the substrate layer 200 is used to coat the active material. Examples include lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium iron phosphate, and ternary materials. Alternatively, graphite or silicon oxide can be used. The conductive layer 300 can be made of copper foil or aluminum foil.

[0074] The conductive layer 300 and the substrate layer 200 are bonded to each other with glue therebetween. The glue material can be selected from a variety of options, such as: the glue material can include one or more of a composition containing a multifunctional isocyanate and a polyester polyol compound, polyurethane, epoxy resin, polyacrylate, polyvinyl acetate, unsaturated polyester, phenolic resin, urea-formaldehyde resin, modified polyolefin resin, silicone resin, ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, acrylic resin, polycarbonate, and polyamide. In some examples, the glue material includes one or more of a composition containing a multifunctional isocyanate and a polyester polyol compound and polyurethane. The polyurethane includes one or more of thermoplastic polyurethane and reactive polyurethane.

[0075] Such a design allows the conductive layer 300 and the substrate layer 200 to be squeezed and sucked at the same time, thereby accelerating the escape of gas between the conductive layer 300 and the substrate layer 200, reducing bubbles between the conductive layer 300 and the substrate layer 200, improving the bonding strength between the conductive layer and the substrate layer 200, reducing the risk of peeling of the conductive layer 300, and helping to improve battery performance.

[0076] According to some embodiments of the present application, referring to FIG. 1 , the support roller 10 and / or the squeezing roller 20 having the exhaust holes 11 are provided with ventilation channels 12 extending along their respective axial directions, and the ventilation channels 12 are connected to the corresponding exhaust holes 11 .

[0077] The ventilation channel 12 is a structure that enables communication between the suction device and the air extraction hole 11. It extends along the axis and can be easily connected to an external air extraction device. For example, a rotatable sealing interface can be provided at one end of the ventilation channel 12. The sealing interface is connected to the suction device. This provides a stable negative pressure environment for the air extraction hole 11 without affecting the rotation of the support roller 10 or the squeeze roller 20. At the same time, an oil seal can be used between the sealing interface and the inner wall of the channel.

[0078] With such a design, the ventilation channel 12 is introduced to facilitate the connection of the suction hole 11 with an external suction device, thereby achieving stable suction of the conductive layer 300 and / or the substrate layer 200 .

[0079] According to some embodiments of the present application, referring to FIG. 1 , in the support roller 10 or the squeezing roller 20 , the exhaust holes 11 include more than two, and at least some of the exhaust holes 11 are distributed at intervals.

[0080] In the support roller 10 or squeeze roller 20, at least some of the air extraction holes 11 may be spaced apart along the respective axes, as shown in FIG2 , or spaced apart around the respective circumferences, as shown in FIG1 . Furthermore, when the support roller 10 or squeeze roller 20 is provided with a ventilation channel 12, each of the air extraction holes 11 is in communication with the ventilation channel 12.

[0081] The shape of the air extraction hole 11 can be designed in various ways, for example, it can be a regular shape such as a circle, an ellipse, a triangle, a square, a pentagon, etc.; it can also be an irregular shape.

[0082] With this design, at least some of the exhaust holes 11 are spaced apart to expand the range of the exhaust, making the exhaust between the conductive layer 300 and the substrate layer 200 more uniform, which is beneficial to improving the pressing quality of the composite current collector.

[0083] According to some embodiments of the present application, referring to FIG. 1 and FIG. 2 , among the spaced apart air extraction holes 11 , the distance between two adjacent air extraction holes 11 is denoted as L, wherein 5 mm ≤ L ≤ 50 mm.

[0084] Adjacent exhaust holes 11 can be spaced along the axis of the support roller 10 or squeeze roller 20. In this case, the distance between the two adjacent exhaust holes 11 is a straight line distance. If the distance between the two adjacent exhaust holes 11 is circumferentially spaced along the support roller 10 or squeeze roller 20, since both the support roller 10 and the squeeze roller 20 are or are approximately cylindrical, the distance between them is the arcuate distance between the two exhaust holes 11. To determine the distance L between two adjacent exhaust holes 11, the center line between the two exhaust holes 11 can be connected. This line can be formed on the surface of the support roller 10 or squeeze roller 20 and located between the two exhaust holes 11 to form a straight line or curved line. This straight line or curved line is the distance L.

[0085] If the value of the spacing L is too large, it will cause a lack of suction in some areas of the conductive layer 300 or the substrate layer 200; if it is too small, it will not only affect the structural strength of the squeezing roller 20 or the support roller 10, but also leave an imprint on the conductive layer 300 or the substrate layer 200, affecting product quality.

[0086] To this end, the distance L may be between 5 mm and 50 mm, such as but not limited to 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, etc. Of course, in other embodiments, the distance L may be between 10 mm ≤ L ≤ 30 mm, such as but not limited to 10 mm, 12 mm, 15 mm, 18 mm, 20 mm, 22 mm, 25 mm, 28 mm, 30 mm, etc.

[0087] With this design, the spacing L is controlled between 5 mm and 50 mm, so that the design of the exhaust holes 11 can effectively take into account both the exhaust effect and the lamination quality between the conductive layer 300 and the substrate layer 200 .

[0088] According to some embodiments of the present application, referring to FIG. 1 , in the support roller 10 or the squeezing roller 20 , the exhaust holes 11 include more than two, and at least some of the exhaust holes 11 are spaced apart and distributed around the periphery of the corresponding axis.

[0089] The exhaust holes 11 are spaced around the periphery of the corresponding axis, which can be understood as follows: when more than two exhaust holes 11 are provided on the support roller 10, at least some of the exhaust holes 11 are spaced around the periphery of the axis of the support roller 10; when more than two exhaust holes 11 are provided on the squeezing roller 20, at least some of the exhaust holes are spaced around the periphery of the axis of the squeezing roller 20; when both the support roller 10 and the squeezing roller 20 are provided with more than two exhaust holes 11, the exhaust holes 11 are spaced around the periphery of their respective corresponding axes.

[0090] With such a design, at least some of the exhaust holes 11 are distributed at intervals around the periphery of the axis, so that the support roller 10 or the squeezing roller 20 has a suction function in the circumferential direction. In this way, the support roller 10 or the squeezing roller 20 can suck the conductive layer 300 or the substrate layer 200 when rotating, thereby improving the exhaust effect.

[0091] According to some embodiments of the present application, please refer to FIG2 , the area of ​​the exhaust hole 11 on the roller surface of the support roller 10 or the squeeze roller 20 is recorded as S, where 0.00785 mm 2 ≤S≤0.785mm 2 .

[0092] The shape of the evacuation holes 11 can be regular, such as circular, oval, or square, or irregular. The area of ​​the evacuation holes 11 affects not only the venting effect but also the quality of the composite current collector press. For example, if the area of ​​the evacuation holes 11 is too small, it can easily become clogged, preventing evacuation. If the area of ​​the evacuation holes 11 is too large, it can easily cause adhesive overflow and leave marks on the surface of the conductive layer 300 or substrate layer 200.

[0093] Therefore, the hole area S of the air extraction hole 11 can be controlled to be 0.00785 square millimeters (mm 2 )~0.785mm 2 For example, it can be but not limited to 0.00785mm 2 , 0.008mm 2 , 0.01mm 2 , 0.1mm 2 , 0.19625mm 2 , 0.2mm 2 , 0.3mm 2 , 0.4mm 2 , 0.5mm 2 , 0.6mm 2 , 0.7mm 2 , 0.785mm 2 When the air extraction hole 11 is a circular hole, the aperture of the air extraction hole 11 may be 0.1 mm to 1 mm, for example, the aperture may be but not limited to 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, etc.

[0094] In addition, in some other embodiments, the hole area S can also be 0.1mm 2 ~0.5mm 2 Of course, if the air extraction hole 11 is a circular hole, the aperture can also be set between 0.36 mm and 0.80 mm.

[0095] With this design, the area of ​​the air extraction hole 11 is controlled at 0.00785mm 2 ~0.785mm 2 Effective exhaust can be achieved; at the same time, the probability of glue overflow or embossing during the pressing process can be reduced, thereby improving the pressing quality.

[0096] According to some embodiments of the present application, referring to FIG. 1 , the squeezing rollers 20 include more than two, and all the squeezing rollers 20 are spaced apart and distributed around the circumference of the axis of the supporting roller 10 .

[0097] By disposing two or more squeeze rollers 20 at intervals on the periphery of the support roller 10, the same portion of the composite current collector can pass through different squeeze rollers 20 in sequence, achieving multi-stage lamination and strengthening the bond between the conductive layer 300 and the substrate layer 200. Furthermore, when passing through different squeeze rollers 20, the squeezing force exerted by each squeeze roller 20 on the conductive layer 300 and the substrate layer 200 can remain the same or different. For example, as the same portion of the conductive layer 300 and the substrate layer 200 passes through different squeeze rollers 20 in sequence, the pressure exerted by the squeeze rollers 20 gradually increases.

[0098] On the same support roller 10 , the number of squeezing rollers 20 is not limited to the three shown in FIG. 1 , but may be other numbers, such as 2, 4, 5 or more.

[0099] For ease of understanding, let's use three squeezing rollers 20 as an example. During the lamination process, the conductive layer 300 and the substrate layer 200 pass sequentially between the three squeezing rollers 20 and the support roller 10. The pressure applied by the first squeezing roller 20 can be controlled between 5 and 30 tons, the pressure applied by the second squeezing roller 20 can be controlled between 30 and 40 tons, and the pressure applied by the third squeezing roller 20 can be controlled between 40 and 50 tons. This gradually increases the pressing force between the conductive layer 300 and the substrate layer 200, allowing for the gradual expulsion of gas without causing wrinkles in the substrate layer 200. Furthermore, the three-stage extrusion process allows for more effective lamination between the conductive layer 300 and the substrate layer 200, allowing for more efficient gas expulsion from the interface.

[0100] In addition, each squeeze roller 20 can be configured to independently press or release, facilitating adjustment during the composite current collector run. For example, each squeeze roller 20 is secured with an adjustment bolt. When the adjustment bolt is needed, the adjustment bolt is loosened, allowing the squeeze roller 20 to move away from the support roller 10. Alternatively, each squeeze roller 20 can be equipped with a pneumatic, electric, or hydraulic cylinder.

[0101] With this design, more than two squeezing rollers 20 are introduced to squeeze the same portion of the conductive layer 300 and the substrate layer 200 multiple times, thereby enhancing the pressing effect and making the conductive layer 300 and the substrate layer 200 tightly bonded; at the same time, it also enhances the exhaust effect and reduces the chance of peeling of the conductive layer 300.

[0102] According to some embodiments of the present application, please refer to Figure 1, a lamination path 13 is formed between all the extrusion rollers 20 and the support roller 10 for the stacked conductive layer 300 and the substrate layer 200 to pass through, and the central angle corresponding to the lamination path 13 on the support roller 10 is recorded as θ, where 180°≤θ<360°.

[0103] The lamination path 13 refers to the path formed by the conductive layer 300 and the base material layer 200 as they travel on the support roller 10. Since the conductive layer 300 and the base material layer 200 are pressed on the support roller 10 by the squeezing roller 20, the lamination path 13 can also be understood as the path formed along the roller surface of the support roller 10 from the pressing point of the first squeezing roller 20 on the support roller 10 to the pressing point of the last squeezing roller 20 on the support roller 10.

[0104] When the squeezing roller 20 and the supporting roller 10 are both constructed as cylindrical structures, when determining the central angle of the lamination path 13, the axis of the first squeezing roller 20 can be connected with the axis of the supporting roller 10; then the axis of the last squeezing roller 20 can be connected with the axis of the supporting roller 10, and the angle between the two connecting lines is the central angle of the lamination path 13.

[0105] The central angle θ is greater than or equal to 180°. For example, the central angle θ can be, but is not limited to, 180°, 190°, 200°, 210°, 225°, 270°, 300°, and 330°. Controlling the central angle θ to be greater than or equal to 180° increases the wrap angle of the conductive layer 300 and the substrate layer 200 on the support roller 10, thereby increasing the contact surface between the composite current collector and the support roller 10 and enhancing the lamination and degassing effects. Furthermore, if the support roller 10 can be heated, this can also increase the heated surface area of ​​the composite current collector during the lamination process.

[0106] Of course, in some other embodiments, the central angle θ may also be between 200° and 300°.

[0107] With this design, the central angle of the pressing path 13 is controlled to be greater than or equal to 180°, which can increase the running angle of the conductive layer 300 and the substrate layer 200 on the support roller 10, and is conducive to improving the pressing and exhaust effects of the composite current collector.

[0108] According to some embodiments of the present application, referring to FIG. 3 , the cross-sectional area of ​​at least one squeezing roller 20 perpendicular to its own axis first gradually increases from one end of the squeezing roller 20 to the other end of the squeezing roller 20 and then gradually decreases.

[0109] As can be seen, at least one squeezing roller 20 has a larger middle portion and smaller ends. This allows the middle portion to exert relatively greater pressure during lamination, driving the conductive layer 300 and substrate layer 200 toward the ends during lamination. This also helps to displace bubbles in the glue toward the ends.

[0110] The number of squeeze rollers 20 in this structure can be one or more. When there is only one squeeze roller 20 in this structure, it can be placed at a position where it can preferentially press against the same portion of the composite current collector compared to the other squeeze rollers 20. That is, the squeeze roller 20 in this structure is located upstream of the other squeeze rollers 20 on the composite current collector conveying path.

[0111] Specifically, in some embodiments, the squeezing roller 20 is constructed as a cylindrical structure, and the roller surface diameter of the squeezing roller 20 gradually decreases from the middle to the two ends of the squeezing roller 20 .

[0112] To facilitate understanding of the cross section of the squeezing roller 20 perpendicular to its own axis, FIG. 3 may be taken as an example. The cross section of the squeezing roller 20 may be the section line region indicated by T in FIG. 3 .

[0113] In this design, at least one squeezing roller 20 is designed to have a larger middle part and smaller two ends, so that the conductive layer 300 and the substrate layer 200 are more flat during the pressing process; at the same time, it is also beneficial for the bubbles in the glue to transfer to the two ends, thereby improving the exhaust effect.

[0114] According to some embodiments of the present application, please refer to Figure 3. In a plane passing through the axis of the squeezing roller 20, the projection of the roller surface of the squeezing roller 20 includes at least one contour line 21, and the angle between the contour line 21 and the axis of the squeezing roller 20 is recorded as β, where 1°≤β≤5°.

[0115] There are multiple planes passing through the axis of the squeeze roller 20. Since the roller surface of the squeeze roller 20 is arranged around the periphery of its own axis, to obtain the contour line 21 of the squeeze roller 20, any one of these multiple planes can be selected as the projection plane. The squeeze roller 20 of this embodiment has a relatively large intermediate size. Therefore, the projection within this plane will result in at least one contour line 21 intersecting the axis of the squeeze roller 20.

[0116] The angle β may be between 1° and 5°, for example, but not limited to, 1°, 2°, 3°, 4°, 5°, etc. In other embodiments, the angle β may be between 2° and 4°.

[0117] With this design, the angle β is reasonably controlled to be between 1° and 5°, thereby achieving a better flattening effect on the conductive layer 300 and the substrate layer 200 and improving the lamination quality.

[0118] According to some embodiments of the present application, the squeezing mechanism 100 further includes a heating component (not shown), which is used to heat the roller surface of the support roller 10 and / or the squeezing roller 20 .

[0119] The heating component refers to a device that can generate heat, which can be an electric heating device, such as an electric heating wire, an electric heating tube, etc.; it can also be a heat transfer oil device, such as passing heated oil into the interior of the support roller 10 and / or the squeeze roller 20 to heat the roller surface.

[0120] When the support roller 10 and / or the squeeze roller 20 are heated, they transfer heat to the surface of the conductive layer 300 and / or the substrate layer 200, softening the glue between the conductive layer 300 and the substrate layer 200 and strengthening the bond between the two. Of course, the heated surface also makes it easier for bubbles to escape, enhancing the degassing effect.

[0121] Such a design introduces a heating component to increase the surface temperature of the conductive layer 300 and / or the substrate layer 200, soften the glue, and improve the bonding performance; at the same time, it also makes it easier for bubbles in the glue to escape, thereby improving the exhaust effect.

[0122] According to some embodiments of the present application, please refer to FIG. 1 , each of the support rollers 10 and the squeeze rollers 20 includes more than two, all the support rollers 10 are arranged in parallel and spaced apart, and each support roller 10 cooperates with at least one squeeze roller 20 .

[0123] "Parallel and spaced support rollers 10" means that the support rollers 10 are spaced apart from each other, and the axes of the support rollers 10 are parallel or substantially parallel to each other. During the lamination process, the conductive layer 300 and the substrate layer 200 can be sequentially wound around each support roller 10, so that the conductive layer 300 and the substrate layer 200 are laminated on each support roller 10. Each support roller 10 can be equipped with one squeeze roller 20, or multiple squeeze rollers 20 can be configured simultaneously.

[0124] All the support rollers 10 may be arranged side by side and spaced apart along the same straight line direction, or may be arranged side by side and spaced apart along different straight line directions, as long as the axes of the support rollers 10 are parallel or approximately parallel to each other.

[0125] With such a design, more than two supporting rollers 10 are introduced, so that the conductive layer 300 and the base material layer 200 are pressed on different supporting rollers 10 in sequence, thereby enhancing the bonding strength and improving the stability of the structure.

[0126] According to some embodiments of the present application, please refer to FIG4 , the present application provides a composite current collector preparation device, comprising any one of the above extrusion mechanisms 100 .

[0127] The above-mentioned composite current collector preparation device adopts the above-mentioned extrusion mechanism 100, so that the conductive layer 300 and the substrate layer 200 are squeezed and sucked at the same time, thereby accelerating the gas escape between the conductive layer 300 and the substrate layer 200, reducing the bubbles between the conductive layer 300 and the substrate layer 200, improving the bonding force between the conductive layer and the substrate layer 200, reducing the risk of peeling of the conductive layer 300, and helping to improve battery performance.

[0128] According to some embodiments of the present application, the composite current collector preparation device also includes a punching mechanism 30. On the conveying path of the substrate layer 200 or the conductive layer 300, the punching mechanism 30 is located at the upstream end of the extrusion mechanism 100 and is used to punch the conductive layer 300 and / or the substrate layer 200.

[0129] The punching mechanism 30 refers to a device capable of forming a hole structure on the conductive layer 300 or the substrate layer 200 , and may be, but is not limited to, a laser punching device, a mechanical drill, or the like.

[0130] The punching mechanism 30 is located upstream of the extrusion mechanism 100. This means that the conductive layer 300 and the substrate layer 200 are first punched with holes by the punching mechanism 30, and then extruded by the extrusion mechanism 100. The punching mechanism 30 is located upstream of the extrusion mechanism 100 to ensure that holes are formed in the conductive layer 300 and / or the substrate layer 200 during lamination. This allows gas to escape through these holes during lamination, enhancing the degassing effect.

[0131] During the punching process, the holes on the conductive layer 300 or the substrate layer 200 can be determined according to the actual product. For example, the diameter of the holes can be controlled to be 50 micrometers (μm) to 500 μm, and the spacing between the holes can be 5 mm to 50 mm.

[0132] With this design, the punching mechanism 30 is used to provide holes on the conductive layer 300 and / or the substrate layer 200, which facilitates the escape of gas from the holes during pressing, further improving the exhaust effect, thereby making the connection between the conductive layer 300 and the substrate layer 200 more stable.

[0133] According to some embodiments of the present application, referring to FIG4 , the composite current collector preparation apparatus further includes a glue coating mechanism 40 on the tape path of the substrate layer 200 or the conductive layer 300. The glue coating mechanism 40 is located at the upstream end of the extrusion mechanism 100 and is used to coat the conductive layer 300 and / or the substrate layer 200 with glue.

[0134] The gluing mechanism 40 refers to a device for applying glue to the conductive layer 300 and / or the substrate layer 200. The gluing mechanism 40 can be set on the tape path of the substrate layer 200 or on the tape path of the conductive layer 300. Of course, the gluing mechanism 40 can be set on the tape paths of the substrate layer 200 and the conductive layer 300 respectively.

[0135] The gluing mechanism 40 is located upstream of the extrusion mechanism 100. Its purpose is to ensure that the conductive layer 300 and / or substrate layer 200 first passes through the gluing mechanism 40 for gluing before entering the extrusion mechanism 100. Upon entering the extrusion mechanism 100, the surfaces of the conductive layer 300 and / or substrate layer 200 coated with glue adhere to each other, causing the support roller 10 and the extrusion roller 20 to contact the uncoated surfaces.

[0136] The gluing mechanism 40 can be of various options, such as, but not limited to, a gravure coating mechanism. To reduce bubbles in the glue, a stirring device with an air extraction function can be provided. During glue stirring, the air pressure within the stirring device can be controlled within a range of 10,000 Pa to 50,000 Pa, such as 10,000 Pa, 20,000 Pa, 30,000 Pa, 40,000 Pa, or 50,000 Pa. Furthermore, during glue application, the glue thickness can be controlled within a range of 0.5 μm to 5 μm, such as 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, or 5 μm.

[0137] With such a design, the adhesive coating mechanism 40 can stably coat the conductive layer 300 and / or the base layer 200 with adhesive, so that the conductive layer 300 and the base layer 200 are stably bonded.

[0138] According to some embodiments of the present application, please refer to Figure 4, the composite current collector preparation device also includes a surface treatment mechanism 60, which is located at the upstream end of the coating mechanism 40 and is used to improve the surface energy of the conductive layer 300 and / or the substrate layer 200.

[0139] The surface treatment mechanism 60 is a device that improves the surface energy of the conductive layer 300 and / or substrate layer 200, making it easier for the glue to adhere to the conductive layer 300 or substrate layer 200. Surface energy refers to the non-volume work required to reversibly increase the surface area of ​​a system under constant temperature, constant pressure, and constant composition, which can enhance the adhesive's adhesion. Examples include surface tension and wettability of the conductive layer 300 or substrate layer 200.

[0140] The surface treatment mechanism 60 may be, but is not limited to, a corona roller, a pit etching device, etc. When the surface treatment mechanism 60 is a corona roller, the surface energy of the conductive layer 300 or the substrate layer 200 may be changed by ionizing air and bombarding the film surface with charged ions under the action of an electric field.

[0141] With this design, the surface treatment mechanism 60 improves the surface energy of the conductive layer 300 and / or the substrate layer 200 , thereby enhancing adhesion to the glue, thereby stably combining the conductive layer 300 and the substrate layer 200 and improving structural stability.

[0142] According to some embodiments of the present application, please refer to Figure 4, the composite current collector preparation device also includes a baking mechanism 50, which is located at the downstream end of the coating mechanism 40 and is used to dry the conductive layer 300 and / or substrate layer 200 after coating.

[0143] The baking mechanism 50 is a device that bakes the glue to remove some of the solvent in the glue. During the drying process, the solvent in the glue is at least partially volatilized, reducing bubbles caused by residual solvent. At the same time, the glue is softened, ensuring stable bonding between the conductive layer 300 and the substrate layer 200.

[0144] The baking mechanism 50 can be designed in many ways, for example, a nozzle can be provided in the baking mechanism 50 to blow out hot air. The baking temperature of the baking mechanism 50 can be 80°C to 150°C, such as but not limited to 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, etc. At the same time, the blowing speed is 0.5m 3 / min~5m 3 / min, such as: 0.5m 3 / min、1m 3 / min、2m 3 / min、3m 3 / min、4m 3 / min、5m 3 / min, etc., and the blowing time can be 2S to 10S, such as: 2S, 3S, 4S, 5S, 6S, 7S, 8S, 9S, 10S, etc. It should be noted that the blowing time can be understood as follows: since the composite current collector is continuously transported, the blowing time is the time it takes to act on a certain part of the conductive layer 300 and / or substrate layer 200; it can also be understood as the time it takes for a certain part of the conductive layer 300 and / or substrate layer 200 to pass through a certain area formed by the blowing of the nozzle.

[0145] With such a design, the baking mechanism 50 is introduced to accelerate the volatilization of the solvent in the glue, soften the glue, improve the bonding performance, and further improve the bonding force between the conductive layer 300 and the substrate layer 200 .

[0146] According to some embodiments of the present application, referring to FIG. 4 , the composite current collector preparation device further includes a passivation mechanism 70 , which is used to passivate at least one surface of the conductive layer 300 .

[0147] The passivation mechanism 70 is a device capable of forming a passivation layer on the surface of the conductive layer 300. The passivation agent used therein can be selected from a variety of options, for example, the passivation agent includes one or more of organic phosphates, chromates, dichromates, Al2O3, SiO2, and Si3N4. Among them, the organic phosphate includes one or more of hydroxyethylidene diphosphonic acid, diethylenetriamine penta (methylene phosphonic acid), triethylenetetraamine hexa (methylene phosphonic acid), and ethylenediamine tetra (methylene phosphonic acid). Chromate includes one or more of sodium chromate, potassium chromate, magnesium chromate, and silver chromate. Dichromate includes one or more of ammonium dichromate, potassium dichromate, sodium dichromate, and magnesium dichromate.

[0148] When a passivation layer is formed on the surface of the conductive layer 300, the corrosion resistance of the conductive layer 300 under long-term circulation storage in the electrolyte can be improved, thereby further improving the peeling force and reliability between the substrate layer 200 and the conductive layer 300, and further reducing the peeling risk of the composite current collector under long-term immersion in the electrolyte.

[0149] At the same time, when the passivation mechanism 70 passivates the surface of the conductive layer 300 facing the substrate layer 200 , the adhesion of the conductive layer 300 to the glue can be increased, thereby improving the bonding strength.

[0150] In addition, when the passivation mechanism 70 and the surface treatment mechanism 60 (such as a corona roller) are introduced simultaneously on the conveying path of the conductive layer 300, the passivation mechanism 70 can be located at the downstream end of the surface treatment mechanism 60, so that after the surface treatment, the passivation layer can better infiltrate the conductive layer 300.

[0151] Such a design and the introduction of a passivation layer can improve the corrosion resistance of the conductive layer 300 under long-term circulation storage of the electrolyte and reduce the risk of peeling of the composite current collector under long-term immersion in the electrolyte; at the same time, it also improves the adhesion of the conductive layer 300 to the glue, further improving the stability of the structure.

[0152] According to some embodiments of the present application, referring to FIG. 4 , the composite current collector preparation device further includes a first unwinding mechanism 80 and a second unwinding mechanism 81 , which are used to release the conductive layer 300 and the substrate layer 200 , respectively.

[0153] The first unwinding mechanism 80 is used to release the conductive layer 300, and the second unwinding mechanism 81 is used to release the substrate layer 200. Both structures can be designed to be cylindrical or disc-shaped. The number of first unwinding mechanisms 80 can be one or more. When there are multiple first unwinding mechanisms 80, two first unwinding mechanisms 80 are used to release the conductive layer 300 onto the two surfaces of the substrate layer 200, respectively, so that the composite current collector can be formed in one step.

[0154] Furthermore, when the two first unwinding mechanisms 80 release the conductive layer 300 onto the two surfaces of the substrate layer 200, respectively, the two first unwinding mechanisms 80 can be located on opposite sides of the tape path of the substrate layer 200, and the two first unwinding mechanisms 80 can release the conductive layer 300 onto the same support roller 10, as shown in FIG5 , or onto different support rollers 10, as shown in FIG6 . For example, referring to FIG6 , the conductive layer 300 released by the first unwinding mechanism 80 and the substrate layer 200 released by the second unwinding mechanism 81 enter between one of the support rollers 10 and the squeezing roller 20, so that a layer of the conductive layer 300 adheres to one surface of the substrate layer 200. Then, the conductive layer 300 released by the other first unwinding mechanism 80 and the substrate layer 200 with the conductive layer 300 adhered thereto enter between the other support roller 10 and the squeezing roller 20.

[0155] With this design, the first unwinding mechanism 80 and the second unwinding mechanism 81 are introduced, so that the preparation of the composite current collector can be carried out continuously and stably.

[0156] According to some embodiments of the present application, referring to FIG. 4 , the composite current collector preparation device further includes a winding mechanism 90 , which is used to wind up the laminated conductive layer 300 and the substrate layer 200 output by the extrusion mechanism 100 .

[0157] The winding mechanism 90 is used to roll up the base material layer 200 bonded and pressed with the conductive layer 300 , and can be designed into a cylindrical or disc-shaped structure.

[0158] With such a design, the composite current collector can be easily stored through the winding mechanism 90 .

[0159] According to some embodiments of the present application, please refer to FIG7 , the present application provides a method for preparing a composite current collector, the method comprising the following steps:

[0160] S100, drilling holes through the surface of the substrate layer 200 and / or the conductive layer 300;

[0161] S200, applying glue to the surface of the substrate layer 200 and / or the conductive layer 300;

[0162] S300, laminating and bonding the substrate layer 200 and the conductive layer 300;

[0163] S400 , pressing and exhausting the laminated substrate layer 200 and the conductive layer 300 .

[0164] The “and / or” in step S100 is not necessarily related to the “and / or” in step S200. For example, in step S100, the substrate layer 200 is punched, and in step S200, the substrate layer 200 may be coated with glue, and the conductive layer 300 may also be coated with glue; in step S100, the conductive layer 300 is punched, and in step S200, the substrate layer 200 may be coated with glue, and the conductive layer 300 may also be coated with glue, etc.

[0165] Meanwhile, the execution order between step S100 and step S200 can be various, for example, punching can be performed first, then gluing; or gluing can be performed first, then punching. Specifically, in some embodiments, step S100 is performed first, and then step S200 is performed.

[0166] By drilling through the surface of the substrate layer 200 and / or the conductive layer 300, holes can be formed through the substrate layer 200 and / or the conductive layer 300. This allows bubbles in the glue to escape through these holes during lamination. Regarding the size of the holes, reference can be made to the hole designs in the above embodiments. Furthermore, regarding the material requirements for the substrate layer 200 and the conductive layer 300, reference can also be made to the above embodiments and will not be elaborated upon here.

[0167] In step S300, the number of conductive layers 300 can be one or two. When there are two conductive layers 300, the two conductive layers 300 are respectively bonded to the two opposite surfaces of the substrate layer 200 using glue. When there is only one conductive layer 300, after laminating the conductive layer 300 on one surface, steps S100 to S400 can be repeated.

[0168] In step S400, the substrate layer 200 and the conductive layer 300 are squeezed to ensure a tight bond between them. During the squeezing process, air is extracted to expel bubbles from the glue between the substrate layer 200 and the conductive layer 300, reducing the chance of delamination of the conductive layer 300. There are various ways to implement this air extraction, such as performing the squeezing operation in a negative pressure environment or using the squeezing roller 20 and support roller 10 described in the above embodiments. Of course, the preparation method of this embodiment can also utilize the composite current collector preparation device described in any of the above embodiments.

[0169] With such a design and the preparation method, the conductive layer 300 and the substrate layer 200 are squeezed and sucked at the same time, which accelerates the gas escape between the conductive layer 300 and the substrate layer 200, reduces the bubbles between the conductive layer 300 and the substrate layer 200, improves the bonding force between the conductive layer and the substrate layer 200, reduces the risk of peeling of the conductive layer 300, and is beneficial to improving battery performance.

[0170] According to some embodiments of the present application, referring to FIG. 8 , S400 , the step of extruding and degassing the laminated substrate layer 200 and the conductive layer 300 includes:

[0171] S410, passing the laminated substrate layer 200 and the conductive layer 300 between the support roller 10 and the squeeze roller 20;

[0172] S420 , the base material layer 200 and the conductive layer 300 are squeezed and transported by the support roller 10 and the squeezing roller 20 ;

[0173] S430 , exhausting air from the exhaust holes 11 on the roller surface of the support roller 10 and / or the squeezing roller 20 .

[0174] The support roller 10 and the squeeze roller 20 are structures acting on opposite sides of the composite current collector, and both can be cylindrical structures. Of course, the features of the support roller 10 and the squeeze roller 20 can refer to the support roller 10 and the squeeze roller 20 in any of the above embodiments, and will not be repeated here.

[0175] Such a design introduces the support roller 10 and the squeezing roller 20, so that squeezing and suction can be achieved at the same time during the pressing process, thereby accelerating the discharge of gas from the holes on the conductive layer 300 and / or the substrate layer 200, improving the exhaust effect, and ensuring stable bonding between the conductive layer 300 and the substrate layer 200.

[0176] According to some embodiments of the present application, in the step of extruding and conveying the substrate layer 200 and the conductive layer 300 by cooperating with the support roller 10 and the squeezing roller 20, the squeezing roller 20 includes more than two, and the substrate layer 200 and the conductive layer 300 pass between each squeezing roller 20 and the support roller 10 in turn, and along the running direction of the substrate layer 200, the pressure applied by each squeezing roller 20 on the same support roller 10 gradually increases.

[0177] It can be seen that by disposing two or more squeeze rollers 20 at intervals on the periphery of the support roller 10, the same portion of the composite current collector can pass through different squeeze rollers 20 in sequence, achieving multi-stage lamination and strengthening the bond between the conductive layer 300 and the substrate layer 200. At the same time, when passing through different squeeze rollers 20, the squeezing force exerted by each squeeze roller 20 on the conductive layer 300 and the substrate layer 200 can remain the same or different. For example, as the same portion of the conductive layer 300 and the substrate layer 200 passes through different squeeze rollers 20 in sequence, the pressure exerted by the squeeze rollers 20 gradually increases.

[0178] On the same support roller 10 , the number of squeezing rollers 20 is not limited to the three shown in FIG. 1 , but may be other numbers, such as 2, 4, 5 or more.

[0179] In addition, each squeeze roller 20 can be configured to independently press or release, facilitating adjustment during the composite current collector run. For example, each squeeze roller 20 is secured with an adjustment bolt. When the adjustment bolt is needed, the adjustment bolt is loosened, allowing the squeeze roller 20 to move away from the support roller 10. Alternatively, each squeeze roller 20 can be equipped with a pneumatic, electric, or hydraulic cylinder.

[0180] With this design, more than two squeezing rollers 20 are introduced to squeeze the same portion of the conductive layer 300 and the substrate layer 200 multiple times, thereby enhancing the pressing effect and making the conductive layer 300 and the substrate layer 200 tightly bonded; at the same time, it also enhances the exhaust effect and reduces the chance of peeling of the conductive layer 300.

[0181] According to some embodiments of the present application, referring to FIG. 9 , after S200 , the step of applying glue to the surface of the substrate layer 200 and / or the conductive layer 300 , the process further includes:

[0182] S500 , baking the base material layer 200 and / or the conductive layer 300 coated with glue.

[0183] The purpose of baking is to volatilize the solvent in the glue and reduce the chance of subsequent bubbles caused by solvent residue; at the same time, it can also soften the glue and improve the bonding performance.

[0184] Such a design and the introduction of a baking process can reduce the generation of bubbles; at the same time, it is also beneficial to the bonding performance of the glue, so that the conductive layer 300 and the substrate layer 200 are tightly connected.

[0185] According to some embodiments of the present application, the baking parameters include at least one of the following: the blowing speed on the surface of the substrate layer 200 and / or the conductive layer 300 is 0.5 m / s; 3 / min~5m 3 / min; the blowing time on the surface of the substrate layer 200 and / or the conductive layer 300 is 2s to 10s; and the baking temperature is 80°C to 150°C. It should be noted that the blowing time can be understood as: since the composite current collector is continuously transported, the blowing time is the time it takes to act on a certain part of the conductive layer 300 and / or the substrate layer 200; it can also be understood as the time it takes for a certain part of the conductive layer 300 and / or the substrate layer 200 to pass through a certain area formed by the blowing of the nozzle.

[0186] The baking temperature should be neither too high nor too low. A temperature that is too low will not soften the glue and will not eliminate the solvent in the glue. A temperature that is too high will cause the glue to burn and even damage the structure of the substrate layer 200. Therefore, the baking temperature should be controlled to be greater than the softening temperature of the glue but less than the melting point of the substrate layer 200.

[0187] To this end, the baking temperature may be 80°C to 150°C, such as but not limited to 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, etc.

[0188] At the same time, blowing can accelerate the volatilization of the solvent in the glue, and the blowing speed is 0.5m 3 / min~5m 3 / min, such as: 0.5m 3 / min、1m 3 / min、2m 3 / min、3m 3 / min、4m 3 / min、5m 3 / min, etc., and the blowing time can be 2S~10S, such as: 2S, 3S, 4S, 5S, 6S, 7S, 8S, 9S, 10S, etc.

[0189] In this way, the baking temperature, blowing speed and blowing time are reasonably controlled to further reduce the residual solvent in the glue and improve the adhesive performance of the glue, thereby improving the adhesive force between the conductive layer 300 and the substrate layer 200.

[0190] According to some embodiments of the present application, referring to FIG. 9 , before step S200 of applying glue to the surface of the substrate layer 200 and / or the conductive layer 300, the process further includes:

[0191] S600 , performing corona treatment on the surface of the substrate layer 200 and / or the conductive layer 300 .

[0192] Corona treatment involves ionizing air and bombarding the film surface with charged ions under the influence of an electric field. This improves the surface energy of the conductive layer 300 or substrate layer 200 and enhances the wettability of the glue on the conductive layer 300 or substrate layer 200. Corona treatment also cleans the surface of the conductive layer 300 or substrate layer 200. Corona treatment employs equipment such as a corona roller, a discharge electrode, and a power supply.

[0193] In addition, before performing step S300, the conductive layer 300 may be passivated, for example, by using one or more passivating agents selected from organic phosphates, chromates, dichromates, Al2O3, SiO2, and Si3N4 to passivate the conductive layer 300 so that a passivation layer is formed on its surface. When a passivation layer is formed on the surface of the conductive layer 300, the corrosion resistance of the conductive layer 300 under long-term circulation storage of the electrolyte can be improved, thereby further improving the peeling force and reliability between the substrate layer 200 and the conductive layer 300, and further reducing the risk of peeling of the composite current collector under long-term immersion in the electrolyte. Of course, the passivation treatment can be performed in step S600, so that the wettability of the surface of the conductive layer 300 is changed by corona discharge, making it easier for the passivation layer to be bonded to the surface of the conductive layer 300.

[0194] This design introduces a corona treatment step, which improves the corrosion resistance of the conductive layer 300 under long-term circulation storage in the electrolyte and reduces the risk of peeling of the composite current collector under long-term immersion in the electrolyte; at the same time, it also improves the adhesion of the conductive layer 300 to the glue, further improving the stability of the structure.

[0195] According to some embodiments of the present application, the present application provides a battery production system, which includes any of the above composite current collector preparation devices.

[0196] According to some embodiments of the present application, please refer to Figures 1 to 9. The present application provides a composite current collector preparation device, including a first unwinding mechanism 80, a second unwinding mechanism 81, an extrusion mechanism 100 and a winding mechanism 90. The extrusion mechanism 100 includes a support roller 10 and a plurality of extrusion rollers 20 arranged at intervals along the circumference of the support roller 10. The first unwinding mechanism 80 releases the conductive layer 300 between the support roller 10 and the extrusion roller 20, and the second unwinding mechanism 81 releases the substrate layer 200 between the support roller 10 and the extrusion roller 20, and makes the substrate layer 200 overlap with the conductive layer 300. On the conveying path of the conductive layer 300, a punching mechanism 30, a surface treatment mechanism 60 (such as a corona module) and a passivation mechanism 70 are sequentially provided. On the conveying path of the substrate layer 200, a punching mechanism 30, a surface treatment mechanism 60 (such as a corona module), a glue coating mechanism 40 and a baking mechanism 50 are sequentially provided.

[0197] Below, the embodiment of the present application is described. The embodiment described below is exemplary, is only used to explain the present application, and is not to be construed as limiting the present application. Where the technology or conditions are not specified in the embodiment, the technology or conditions described in the literature in this area or the product instructions are used. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be obtained commercially.

[0198] Example 1

[0199] The base material layer 200 and the conductive layer 300 are threaded

[0200] The conductive layer 300 is made of aluminum foil with a thickness of 10 μm and a width of 600 mm. The base layer 200 is made of PET (polyethylene glycol terephthalate) with a thickness of 6 μm and a width of 600 mm. The glue is modified polypropylene. The conductive layer 300 and base layer 200 are superimposed and inserted between the squeeze roller 20 and the support roller 10.

[0201] Punching

[0202] A laser puncher is used at the upstream end of the extrusion mechanism 100 to perform online punching on the conductive layer 300 and the base material layer 200 . The hole diameters on the conductive layer 300 and the base material layer 200 are 200 μm, and the hole spacing is 10 mm.

[0203] corona treatment

[0204] The conductive layer 300 and the base material layer 200 after being punched are subjected to an online corona treatment, wherein the corona voltage is 15 kV.

[0205] Glue coating

[0206] The glue was coated on one surface of the substrate layer 200 in-line using a gravure coating roller, and the thickness of the glue was 1 μm.

[0207] Baking

[0208] The coated substrate layer 200 is air-baked online at a temperature of 100°C and an air-blow speed of 1 m 3 / min, and the blowing time at any position on the surface of the substrate layer 200 is controlled to be 5s.

[0209] Passivation treatment

[0210] The surface of the metal aluminum foil is coated with a passivation material, sodium chromate, and then dried at 90°C.

[0211] Extrusion mechanism 100 and extrusion process

[0212] The extrusion mechanism 100 includes two support rollers 10 arranged in parallel and spaced apart, and three extrusion rollers 20 spaced apart on the periphery of each support roller 10. The diameter of the support roller 10 is 600 mm, the center distance between the two support rollers 10 is 1800 mm, and the center angle between any two adjacent extrusion rollers 20 on the support roller 10 is 45°. The roller surface of the support roller 10 is provided with a plurality of exhaust holes 11, the aperture of the exhaust hole 11 is 0.1 mm, and the spacing between the exhaust holes 11 is 5 mm. A ventilation channel 12 connected to each exhaust hole 11 is provided at the axis of each support roller 10, and air is exhausted into the ventilation channel 12. The air pressure in the ventilation channel 12 is 5×10 4 Pa.

[0213] On each support roller 10, the pressure applied to the first squeeze roller 20 along the tape run direction is controlled at 30 tons, the pressure applied to the second squeeze roller 20 is controlled at 40 tons, and the pressure applied to the third squeeze roller 20 is controlled at 50 tons. Furthermore, the diameter of the first squeeze roller 20 gradually decreases from the center toward the ends, with an inclination angle of 3°. The center diameter of the first squeeze roller 20 is 25 mm. The diameters of the remaining two squeeze rollers 20 are 25 mm.

[0214] After the above treatment, a substrate layer 200 having a conductive layer 300 bonded to one surface is obtained; then, the substrate layer 200 having a conductive layer 300 and the conductive layer 300 are re-inserted between the support roller 10 and the squeezing roller 20, and the above punching treatment, corona treatment, glue coating treatment, baking treatment and passivation treatment are repeated to obtain a composite current collector.

[0215] Example 2

[0216] It is basically the same as Example 1, with the only difference being that the diameter of the exhaust hole 11 on the supporting roller 10 is 0.5 mm.

[0217] Example 3

[0218] It is basically the same as Example 1, with the only difference being that the diameter of the air extraction hole 11 on the support roller 10 is 1 mm.

[0219] Example 4

[0220] It is basically the same as Example 2, with the only difference being that the hole spacing between the air extraction holes 11 on the support roller 10 is 20 mm.

[0221] Example 5

[0222] The embodiment is basically the same as the embodiment 2, with the only difference being that the hole spacing between the air extraction holes 11 on the support roller 10 is 50 mm.

[0223] Example 6

[0224] The embodiment is basically the same as the embodiment 4, with the only difference being that each supporting roller 10 has one squeezing roller 20 and the pressure applied by the squeezing roller 20 is 50 tons.

[0225] Example 7

[0226] It is basically the same as Example 4, with the only difference being that: the number of squeezing rollers 20 on each supporting roller 10 is 4, and the pressure applied by the first squeezing roller 20 along the belt-walking direction is 20 tons, the pressure applied by the second squeezing roller 20 is 30 tons, the pressure applied by the third squeezing roller 20 is 40 tons, and the pressure applied by the fourth squeezing roller 20 is 50 tons.

[0227] Example 8

[0228] The method is basically the same as Example 1, with the only difference being that during the preparation process, the conductive layer 300 is not subjected to corona treatment.

[0229] Example 9

[0230] The method is basically the same as Example 1, with the only difference being that during the preparation process, the substrate layer 200 is not subjected to corona treatment.

[0231] Example 10

[0232] It is basically the same as the embodiment 1, with the only difference being that the first support roller 10 along the belt-feeding direction is not subjected to air extraction.

[0233] Example 11

[0234] It is basically the same as the embodiment 1, with the only difference being that air is not exhausted in the second supporting roller 10 along the belt-feeding direction.

[0235] Comparative Example 1

[0236] It is basically the same as Example 1, with the only difference being that the diameter of the exhaust hole 11 on each supporting roller 10 is 0.05 mm.

[0237] Comparative Example 2

[0238] The embodiment is basically the same as the second embodiment, with the only difference being that the hole spacing between the air extraction holes 11 on each supporting roller 10 is 60 mm.

[0239] Comparative Example 3

[0240] The method is basically the same as Example 1, with the only difference being that during the preparation process, neither the conductive layer 300 nor the substrate layer 200 is subjected to corona treatment.

[0241] Comparative Example 4

[0242] The embodiment is basically the same as the embodiment 1, with the only difference being that air is not exhausted in the two support rollers 10 .

[0243] Comparative Example 5

[0244] The method is basically the same as Comparative Example 4, with the only difference being that during the preparation process, neither the conductive layer 300 nor the substrate layer 200 is subjected to corona treatment.

[0245] Comparative Example 6

[0246] The method is basically the same as Comparative Example 5, with the only difference being that each supporting roller 10 has one squeezing roller 20 and the pressure applied by the squeezing roller 20 is 50 tons.

[0247] Comparative Example 7

[0248] It is basically the same as Comparative Example 6, except that: the conductive layer 300 and the base material layer 200 are not perforated, and no exhaust holes 11 are provided on the roller surface of each supporting roller 10.

[0249] The parameters used in each embodiment and each comparative example are shown in Table 1.

[0250] Table 1

[0251] The composite current collectors prepared in each embodiment and comparative example were subjected to a conductive layer 300 peeling test, an adhesion test, an immersion adhesion test, and a 60° C. cycle test in sequence. Specific results can be found in Table 2.

[0252] Conductive layer 300 peeling test

[0253] The sample was cut into pieces with a width of ≥20mm and a length greater than 100mm, fixed on a steel plate with double-sided tape, and a 20mm wide tape (adhesive force 200N / m) was applied to the sample surface for a peel test. The peel test was performed at a speed of 500mm / min and a 180° peeling angle with a peeling area of ​​2000mm. 2 (peeling distance 100mm), and at the same time, the metal chips remaining on the tape were observed under a microscope, and the area of ​​the metal chips was read. The areas of all fallen metal chips were summed to obtain the falling area of ​​the conductive layer of each current collector.

[0254] Adhesion test

[0255] After laminating the sample to the non-corona surface of an ethylene-acrylic acid copolymer (EAA) film, a 12μm-thick PET film was placed on the EAA film and placed on a heat sealer for lamination at a temperature of 120°C and a pressure of 0.2MPa. The laminated sample was cut into 100mm long and 20mm wide specimens, and the non-laminated surface of the conductive layer was attached to a steel plate using 3M double-sided tape. The sample was clamped in the fixture of a tensile testing machine with a spacing of 50mm and a speed of 300mm / min. A 180-degree peel test was performed, and the peel force was read and converted to N / m. Five parallel samples were tested, and the average peel force was finally taken. The average peel force = the sum of the peel forces of the five test samples / 5, which is the bonding strength.

[0256] Immersion adhesion test

[0257] The samples were cut into 3cm×10cm strips, injected with 20mL of electrolyte, sealed in pocket bags, and immersed at 60℃ for 7 days before testing the adhesion strength.

[0258] 60℃ cycle test

[0259] A fresh battery cell is cycled at a 1C rate of charge and discharge at a high temperature of 60°C until the capacity decays to 80% of the initial capacity. The corresponding number of cycles is recorded, which is the corresponding cycle performance of the battery.

[0260] Table 2

[0261] Comparing Examples 1 to 11 with Comparative Example 7, it can be seen that the adhesion, conductive layer peeling area and immersion adhesion of the composite current collector in each embodiment are better than those in Comparative Example 7. At the same time, the number of cycles of the battery at 60°C is better than that of Comparative Example 7, indicating that compared with the composite current collector of the conventional process, the composite current collector of the process of this application is beneficial to improving the adhesion and the cycle performance of the battery.

[0262] Comparison between Example 1, Examples 10-11, Comparative Example 1 and Comparative Example 4 shows that the composite current collector is extruded by vacuuming, and the bonding force, conductive layer peeling area and immersion bonding force of the obtained composite current collector are all better than those of Comparative Example 4; at the same time, vacuuming is used in both extrusion processes, which can further improve the mechanical properties and cycle performance of the composite current collector.

[0263] It can be seen from Examples 1 to 3 and Comparative Example 1 that when the apertures of the air extraction holes 11 are designed to be 0.1 mm, 0.5 mm, and 1 mm, the shedding area of ​​the conductive layer 300 of the composite current collector can be controlled to be 0.1 mm. 2 or 0.2mm 2The current collector adhesion is above 293 N / m, the immersion adhesion is above 285 N / m, and the number of cycles is above 506. At the same time, the performance of the above composite current collectors is better than that of the composite current collector obtained with the pore diameter of the extraction hole 11 being 0.05 mm.

[0264] It can be seen from Example 2, Examples 4-5 and Comparative Example 2 that, compared with Comparative Example 2, when the spacing between the air extraction holes 11 is controlled at 5 mm, 20 mm, and 50 mm, the performance of the obtained composite current collector is better, such as: the shedding area of ​​the conductive layer 300 can be controlled to be no more than 0.3 mm 2 The current collector adhesion is all above 289N / m, the immersion adhesion is all above 280N / m, and the number of cycles is all above 504.

[0265] It can be seen from Examples 4, 6-7 that by arranging two or more squeezing rollers 20 on the same support roller 10 to achieve multi-stage squeezing, the mechanical properties and cycle performance of the obtained composite current collector will be relatively better.

[0266] Comparison of Example 1, Examples 8-9, and Comparative Example 3 shows that corona treatment of both substrate layer 200 and conductive layer 300 can improve the mechanical and cycling performance of the composite current collector. Comparison of Comparative Example 3 with Comparative Examples 5-6 shows that the improvement in composite current collector performance due to air extraction is superior to that achieved with corona treatment.

[0267] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0268] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. An extrusion mechanism, the extrusion mechanism comprising: A support roller (10); An extrusion roller (20) for extruding the mutually adhered conductive layer (300) and substrate layer (200) between the extrusion roller (20) and the support roller (10); Wherein, in the support roller (10) and the extrusion roller (20), at least one of them is provided with air extraction holes (11) on the roller surface provided circumferentially along its own axis for communicating with a suction device.

2. The extrusion mechanism according to claim 1, wherein, An air flow channel (12) extending in the direction of the respective axis is provided on the support roller (10) and / or the extrusion roller (20) having the air extraction holes (11), and the air flow channel (12) communicates with the corresponding air extraction holes (11).

3. The extrusion mechanism according to claim 1 or 2, wherein In the support roller (10) or the extrusion roller (20), there are more than two air extraction holes (11), and at least some of the air extraction holes (11) are spaced apart.

4. The extrusion mechanism according to claim 3, wherein, In the spaced-apart air extraction holes (11), the distance between two adjacent air extraction holes (11) is denoted as L, wherein 5 mm ≤ L ≤ 50 mm.

5. The extrusion mechanism according to claim 4, wherein, The condition that the distance L also satisfies is: 10 mm ≤ L ≤ 30 mm.

6. The extrusion mechanism according to any one of claims 1-5, wherein, In the support roller (10) or the extrusion roller (20), there are more than two air extraction holes (11), and at least some of the air extraction holes (11) are spaced apart around the outer periphery of the corresponding axis.

7. The extrusion mechanism according to any one of claims 1-6, wherein, The hole area of the air extraction hole (11) on the roll surface of the support roll (10) or the extrusion roll (20) is denoted as S, where 0.00785 mm 2 ≤ S ≤ 0.785 mm 2 .

8. The extrusion mechanism according to claim 7, wherein, The condition that the hole area S also satisfies is: 0.1mm 2 ≤ S ≤ 0.5mm 2 .

9. The extrusion mechanism according to claim 7 or 8, wherein The air extraction holes (11) are configured as circular holes, and the diameter of the air extraction holes (11) is: 0.1 mm to 1 mm.

10. The extrusion mechanism according to any one of claims 1-9, wherein, There are more than two extrusion rollers (20), and all the extrusion rollers (20) are spaced apart around the outer periphery of the axis of the support roller (10).

11. The extrusion mechanism according to claim 10, wherein, A pressing path (13) for the stacked conductive layer (300) and the substrate layer (200) to pass through is formed between all the extrusion rollers (20) and the support roller (10), and the central angle corresponding to the pressing path (13) on the support roller (10) is denoted as θ, wherein 180° ≤ θ < 360°.

12. The extrusion mechanism according to claim 11, wherein, The condition that the central angle θ also satisfies is: 200° ≤ θ ≤ 300°.

13. The extrusion mechanism according to any one of claims 1-12, wherein, The cross-sectional area of at least one extrusion roller (20) in a plane perpendicular to its own axis gradually increases first and then gradually decreases from one end of the extrusion roller (20) to the other end.

14. The extrusion mechanism according to claim 13, wherein, In a plane passing through the axis of the extrusion roller (20), the projection of the roller surface of the extrusion roller (20) includes at least one contour line (21), and the angle between the contour line (21) and the axis of the extrusion roller (20) is denoted as β, wherein 1° ≤ β ≤ 5°.

15. The extrusion mechanism according to claim 14, wherein, The condition that the angle β also satisfies is: 2° ≤ β ≤ 4°.

16. The extrusion mechanism according to any one of claims 1-15, wherein, The extrusion mechanism further includes a heating component for heating the roller surfaces of the support roller (10) and / or the extrusion roller (20).

17. The extrusion mechanism according to any one of claims 1-16, wherein, Both the support roller (10) and the extrusion roller (20) include more than two, all the support rollers (10) are arranged side by side and spaced apart, and each support roller (10) cooperates with at least one extrusion roller (20).

18. A composite current collector preparation device, comprising the extrusion mechanism according to any one of claims 1-17.

19. The composite current collector manufacturing apparatus according to claim 18, wherein, The composite current collector preparation device further includes a punching mechanism (30). On the tape running path of the base material layer (200) or the conductive layer (300), the punching mechanism (30) is located at the upstream end of the extrusion mechanism and is used to punch holes in the conductive layer (300) and / or the base material layer (200).

20. The composite current collector manufacturing apparatus according to claim 18 or 19, wherein, The composite current collector preparation device further includes a glue coating mechanism (40). On the tape running path of the base material layer (200) or the conductive layer (300), the glue coating mechanism (40) is located at the upstream end of the extrusion mechanism and is used to coat glue on the conductive layer (300) and / or the base material layer (200).

21. The composite current collector manufacturing device according to claim 20, wherein, The composite current collector preparation device further includes a surface treatment mechanism (60). The surface treatment mechanism (60) is located at the upstream end of the glue coating mechanism (40) and is used to improve the surface energy of the conductive layer (300) and / or the base material layer (200).

22. The composite current collector manufacturing device according to claim 20 or 21, wherein, The composite current collector preparation device further includes a baking mechanism (50). The baking mechanism (50) is located at the downstream end of the glue coating mechanism (40) and is used to dry the conductive layer (300) and / or the base material layer (200) after glue coating.

23. The composite current collector manufacturing apparatus according to any one of claims 18-22, wherein, The composite current collector preparation device further includes a passivation mechanism (70). The passivation mechanism (70) is used to passivate at least one surface of the conductive layer (300).

24. The composite current collector manufacturing device according to any one of claims 18-23, wherein, The composite current collector preparation device further includes a first unwinding mechanism (80) and a second unwinding mechanism (81). The first unwinding mechanism (80) and the second unwinding mechanism (81) are respectively used to release the conductive layer (300) and the base material layer (200) correspondingly.

25. The composite current collector manufacturing apparatus according to any one of claims 18-24, wherein, The composite current collector preparation device further includes a winding mechanism (90). The winding mechanism (90) is used to wind the pressed conductive layer (300) and the base material layer (200) output by the extrusion mechanism.

26. A method for preparing a composite current collector, the method comprising the following steps: Perforating the surface of the base material layer (200) and / or the conductive layer (300) through; Coating glue on the surface of the base material layer (200) and / or the conductive layer (300); Overlaying and bonding the base material layer (200) and the conductive layer (300); Extruding and evacuating the overlaid base material layer (200) and conductive layer (300).

27. The method for preparing the composite current collector according to claim 26, wherein, The step of extruding and evacuating the overlaid base material layer (200) and conductive layer (300) includes: Passing the overlaid base material layer (200) and conductive layer (300) between the support roller (10) and the extrusion roller (20); Cooperating the support roller (10) and the extrusion roller (20) to extrude and convey the base material layer (200) and the conductive layer (300); Evacuating the air extraction holes (11) on the roller surfaces of the support roller (10) and / or the extrusion roller (20).

28. The method for preparing the composite current collector according to claim 27, wherein, In the step of extruding and conveying the base material layer (200) and the conductive layer (300) by the cooperation of the supporting roller (10) and the extrusion roller (20), there are more than two extrusion rollers (20). The base material layer (200) and the conductive layer (300) pass between each extrusion roller (20) and the supporting roller (10) in sequence. Along the running direction of the base material layer (200), the pressure applied by each extrusion roller (20) on the same supporting roller (10) gradually increases.

29. The method for preparing a composite current collector according to any one of claims 26-28, wherein, After the step of applying glue to the surface of the base material layer (200) and / or the conductive layer (300), it further includes: Baking the base material layer (200) and / or the conductive layer (300) coated with glue.

30. The method for preparing the composite current collector according to claim 29, wherein, The parameters of the baking include at least one of the following: The blowing speed of the surface of the substrate layer (200) and / or the conductive layer (300) is 0.5 m 3 / min to 5 m 3 / min; The blowing time for the surface of the base material layer (200) and / or the conductive layer (300) is 2S - 10S; The baking temperature is 80°C - 150°C.

31. The method for preparing the composite current collector according to any one of claims 26-30, wherein Before the step of applying glue to the surface of the base material layer (200) and / or the conductive layer (300), it further includes: Performing corona treatment on the surface of the base material layer (200) and / or the conductive layer (300).

32. A battery production system, the battery production system includes the composite current collector preparation device according to any one of claims 18 - 25.

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